Give Fireball a Purpose in PvP

It puzzles me how such a core Fire Mage ability has pretty much zero use in PvP. I can understand cooldowns and situational abilities, but its awkward for such a core ability to be completely neglected in PvP.

Blizzard should do something about it and integrate it into the 'rotation' for PvP.

Despite frost being "the" pvp spec for almost the entire game. Fireball has almost never been used by fire pvp other than after having sheeped someone. It pretty hard to be able to make some use of such a long casting spell..

Fire has always been burst/mobility but squishy, I don't think its gonna change soon..